#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <cmath>
#include <complex>
#include <cstdio>
#include <ctime>
#include <deque>
#include <fstream>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
using namespace std;

#define all(x) (x).begin(),(x).end()
typedef long long ll;

typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<VI> VVI;

typedef pair<int, int> PII;
typedef vector<PII> VPII;
#define X first
#define Y second
#define mp make_pair

#define two(x) (1<<(x))
#define twoll(x) ((long long)1<<(x))
#define contain(s,x) (((s)&two(x))!=0)
#define containll(s,x) (((s)&twoll(x))!=0)

#define db(a) cout << #a << "=" << a << " "
#define dbn cout << endl
template<class T> void print(vector<T> v) { cout << "["; if (v.size()) cout << v[0]; for (unsigned i = 1; i < v.size(); ++i) cout << ", " << v[i];cout << "]\n"; }
template<class T> void print(vector<vector<T> > v) { cout << "[ ---\n"; if (v.size()) cout << " ", print(v[0]); for (unsigned i = 1; i < v.size(); ++i) cout << " ", print(v[i]); cout << "--- ]\n"; }
template<class T1, class T2> void print(pair<T1, T2> p) { cout << "{" << p.first << ", " << p.second << "}"; }
template<class T1, class T2> void print(vector<pair<T1, T2> > v) { cout << "["; if (v.size()) print(v[0]); for (unsigned i = 1; i < v.size(); ++i) cout << ", ", print(v[i]);cout << "]\n"; }
#define sqr(x) (x)*(x)

template<class T> inline int chkmin(T& a, T b) { if (a>b) {a=b; return 1;} return 0; }
template<class T> inline int chkmax(T& a, T b) { if (a<b) {a=b; return 1;} return 0; }

string STR(int n) { char tmp[20]; sprintf(tmp,"%d",n); return tmp; }
int INT(string s) { return atoi(s.c_str()); }
template <class Ty, class Tx> Ty to(const Tx &x) { Ty y; stringstream ss; ss<<x; ss>>y; return y; }

const int INF = 1000000007;
const double EPS = 1e-10;

char buf[1<<20];

int CUR_CASE;
int TOTAL_CASES;

int pri[105][205];
int poi[105][205];

int main() {
#define SUBMIT 1
#if !SUBMIT
	freopen("DATA.in", "rt", stdin);
	freopen("DATA.ou", "wt", stdout);
	clock_t STARTTIME, ENDTIME;
	STARTTIME = clock();
#endif

	gets(buf);
	TOTAL_CASES = atoi(buf);

	for (CUR_CASE = 1; CUR_CASE <= TOTAL_CASES; ++CUR_CASE) {
		int num_book, num_store;
		gets(buf);
		sscanf(buf,"%d%d",&num_book,&num_store);
		vector<int> book_all;
		for(int j=0; j<num_book; j++)
		{
			gets(buf);
			stringstream ss(buf);
			int price,point,sum = 0;
			int storeIdx = 0;
			while (ss>>price>>point)
				pri[storeIdx][j] = price,poi[storeIdx][j] = point, storeIdx++;
		}
		for (int i = 0; i < num_store; ++i)
		{
			VPII vp;
			for (int j = 0; j < num_book; ++j)
				vp.push_back(mp(poi[i][j],pri[i][j]));
			sort(all(vp));
			reverse(all(vp));
			int pr = 0, pt = 0;
			for (int i = 0; i < vp.size(); ++i)
			{
				int price = vp[i].Y, point = vp[i].X;
				if (pt >= price)
					pt -= price;
				else
					pr += price-pt, pt = 0;
				pt += point;
//				db(pr),db(pt),dbn;
			}
//			dbn;
			book_all.push_back(pr);
		}
		sort(all(book_all));
		printf("%d\n",book_all[0]);
	}

#if !SUBMIT
	ENDTIME = clock();
	cerr << "elapsed time : " << ENDTIME-STARTTIME << "ms";
#endif
	return 0;
}
